The present invention relates generally to bedrail and hookplate assembly and, more particularly, to an apparatus that automatically mounts hookplates to bedrails in an efficient and accurate manner.
Typically, in wooden bed frames, a flat, metal plate having hooks for engaging a post associated with a headboard or footboard, is mounted in a slot or on the side of both ends of a wooden bedrail. The hookplate usually includes multiple apertures through which multiple pins or other fasteners extend in order to securely attach the hookplate to the bedrail. These types of hookplates are standard in the wooden bedrail manufacturing industry.
Conventional bedrail manufacturing plants use manual labor to mount the hookplates to the ends of the bedrails. One of the reasons that manual labor is used is that when mounting the hookplates to the bedrails with the pins, it is important that the apertures in the bedrail are aligned with the apertures in the hookplate. If the apertures are not appropriately aligned, the powerful forces used in inserting the pins cause significant damage to the bedrail and/or the hookplate. For example, the wood surfaces surrounding the apertures become damaged and the hookplate bends out of shape. A human being is able to accurately align the apertures in the bedrail and the hookplate to avoid such damage.
As with any type of manufacturing, economics is of primary importance. The use of manual labor to mount the hookplates to the bedrails is generally associated with costly labor expenses and less than desired manufacturing efficiency.
Thus, there remains a need for an efficient and accurate apparatus that automatically mounts hookplates to bedrails.
The present invention fulfills this need in the art by providing an apparatus that automatically mounts a hookplate to a bedrail including a bedrail transport mechanism that transports a bedrail to a hookplate receiving position, a hookplate feeder that places a hookplate in a hookplate mounting position, and a pin driving mechanism that drives at least one pin through the bedrail and the hookplate to mount the hookplate to the bedrail. The bedrail transport mechanism typically includes pusher dogs that transport the bedrail to the hook receiving position.
In a preferred embodiment the hookplate feeder includes a hookplate hopper that stores a plurality of hookplates. The hopper is preferably positioned above a planar surface such that a single hookplate at a time falls onto the planar surface and rests between a bottom of the hopper and a top of the planar surface. A first hookplate pusher slides between the bottom of the hookplate hopper and the top of the planar surface to push the hookplate that falls from the hookplate hopper to a first position. A second hookplate pusher pushes the hookplate from the first position to the hookplate mounting position. The second hookplate pusher includes a clamp having a first end and a second end, the first end being configured to clamp down onto the hookplate. The clamp includes a fulcrum such that when the second end of the clamp is directed towards the planar surface, the first end of the clamp is directed away from the planar surface. When the clamp is waiting for the hookplate from the first hookplate pusher, the second end of the clamp is held under a clamp base in a position directed toward the planar surface such that first end of the clamp is directed away from the planar surface and is open to receive the hookplate. When the first hookplate pusher pushes the hookplate into the first position, the clamp moves away from the clamp base and a spring supports the second end of the clamp in a position directed away from the planar surface so that the first end of the clamp clamps down on the hookplate. The clamp base includes a roller that holds the second end of the clamp in the position directed toward the planar surface and permits the second end of the clamp to slide away from the clamp base.
The pin driving mechanism preferably includes at least one pin driver that drives the pin through the bedrail and the hookplate. In a first step, the pin driver fully extends into an aperture in the bedrail and an aperture in the hookplate to align the apertures. The pin driver then retracts. A pin supply chamber is provided that stores a plurality of pins. At least one pin is transported from the pin supply chamber to the pin driving mechanism after the pin driver retracts. A pin holding plate is provided that has at least one generally cylindrical opening that temporarily holds the pin after it is transported from the pin supply chamber to the pin driving mechanism. The generally cylindrical opening in the pin holding plate includes a set of spring loaded detents that prevent the pin from passing through the holding plate when the pin first enters the holding plate. The pin driver then drives the pin past the detents and substantially completely through the aperture in the bedrail and the aperture in the hookplate to mount the hookplate to the bedrail.
A plurality of pneumatic cylinders may be used to drive the bedrail transport mechanism, the hookplate feeder, and the pin driving mechanism. The position of the pneumatic cylinders may be detected by electronic sensors. A programmable logic controller may be used to control the plurality of pneumatic cylinders.